An image enhancement technology is one of key technologies in the field of image processing, and the technology is used for improving and promoting quality of an original image, and even revealing information hidden in the original image, so that the original image is more suitable for observation of a human visual system or subsequent processing of another functional module. The image enhancement technology has important application in fields, such as remote sense, dynamic scene analysis, automatic navigation, and medical image analysis.
Currently, performing image enhancement by means of gamma correction is most frequently used in the image enhancement technology, and the principle thereof is performing power transformation on a pixel grayscale of an input image, as shown in the following formula:s=crγwhere, c, γ are positive constants, and r, s are respectively pixel grayscales of an input image and an output image.
Because simple power transformation is performed only on the input image according to the foregoing technology, only an overall luminance of the image can be adjusted, and an enhanced image is rough.